Module: Associatable

Included in:
TGauge::TRecordBase
Defined in:
lib/app/models/associatable.rb

Instance Method Summary collapse

Instance Method Details

#assoc_options ⇒ Object 



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# File 'lib/app/models/associatable.rb', line 114

def assoc_options
  @assoc_options ||= {}
end

#belongs_to(name, options = {}) ⇒ Object

Phase IIIb



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# File 'lib/app/models/associatable.rb', line 36

def belongs_to(name, options = {})
  options = BelongsToOptions.new(name, options)

  define_method(name) do
    fkey_val = self.send(options.foreign_key)
    class_obj = options.model_class

    class_obj.where(options.primary_key => fkey_val).first
  end

  assoc_options[name] = options
end

#has_many(name, options = {}) ⇒ Object 



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# File 'lib/app/models/associatable.rb', line 49

def has_many(name, options = {})
  # ...
  unless options.first[0] == :through
    options = HasManyOptions.new(name, self.to_s, options)

    define_method(name) do
      class_obj = options.model_class
      pr_key = self.send(options.primary_key)
      class_obj.where(options.foreign_key => pr_key)
    end

    assoc_options[name] = options
  else
    options[:source] ||= name
    through(name, options[:through], options[:source])
  end
end

#has_one(name, options = {}) ⇒ Object 



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# File 'lib/app/models/associatable.rb', line 109

def has_one (name, options = {})
  options[:source] ||= name
  through(name, options[:through], options[:source])
end

#through(name, through_name, source_name) ⇒ Object 



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# File 'lib/app/models/associatable.rb', line 67

def through(name, through_name, source_name)
  define_method(name) do
    through_options = self.class.assoc_options[through_name]
    source_options = through_options.model_class.assoc_options[source_name]

    if through_options.is_a?(BelongsToOptions)
      # A to B has a belongs_to relationship
      a_test_key = self.send(through_options.foreign_key)
      b_column = through_options.primary_key
    else
      # A to B has a has_many relationship
      a_test_key = self.send(through_options.primary_key)
      b_column = through_options.foreign_key
    end

    if source_options.is_a?(BelongsToOptions)
      # B to C has a belongs_to relationship
      b_test_key = source_options.foreign_key
      c_column = source_options.primary_key
    else
      # B to C has a has_many relationship
      b_test_key = source_options.primary_key
      c_column = source_options.foreign_key
    end
    source_table = source_options.table_name
    through_table = through_options.table_name

    all_data = DBConnection.execute(<<-SQL)
      SELECT
        #{source_table}.*
      FROM
        #{through_table}
      JOIN
        #{source_table} ON #{source_table}.#{c_column} = #{through_table}.#{b_test_key}
      WHERE
        #{through_table}.#{b_column} = #{a_test_key}
    SQL

    source_options.model_class.parse_all(all_data)
  end
end